Variable names

I just left my basement and I learned that people outside use something else that one- and three-character variable names. Is this true and widespread practice?

One time I wrote a PHP script where I made the variable names ridiculous using wide characters, as in

$ｏｐｅｎ＿ｄｉｒ（”ｗｈａｔ”）；=open_dir("what");